Transcript Meninges of brain & spinal cord(out inward)

Protection & Supply Apparatuses
for Central Nervous System
Meninges of Brain and Spinal Cord
Cerebral Spinal Fluid (CSF) Circulation
Blood Vessels of Brain and Spinal Cord
Guo Ling , MD, PhD
Department of Anatomy
Meninges of Brain and Spinal Cord
Concept：they are the connective tissue membranes
covering the brain and the spinal cord (three layers)
Meninges of
Spinal
Cerebral
brain & spinal
meninges
meninges
cord(out inward)
dura mater
arachnoid
pia mater
cerebral dura
mater
arachnoid
cerebral pia
mater
spinal dura
mater
arachnoid
spinal pia mater
Cerebral dura mater
Arachnoid
Cerebral pia mater
Spinal dura
Spinal pia mater
arachnoid
Spaces Formed by Meninges
& Relative Contents
1.Epidural Space
Location: lying between spinal dura and internal
periosteum of the vertebral canal.
Contents: roots of spinal nerve,venous plexuses,rich fat
Feature: minus atmospheric pressure.
2.Subarachnoid Space
Location: lying between arachnoid
and pia mater.
Contents: cerebrospinal fluid (CSF)
Features: plus pressure equal to the
normal atmospheric pressure
Locally enlarged spaces(5):
terminal cistern(L2—S4)
cerebellomedullary cistern
interpeduncular cistern
pontine cistern
5 positions
superior cistern
Grains:
arachnoid granulations
Specific Structures Formed by Cerebral Dura Mater
1.Inclusion: cerebral falx
cerebellar falx
cerebellar tentorium dural sinuses
2.Communications among the sinuses:
2.Communications among the sinuses:
Sup.sagittal sinus
Inf.sagittal sinus→straight sinus→confluence of
sinuses→transverse sinus→sigmoid sinus→inter jug v
Cavernous sinus → sup.petrosal sinus
inf.petrosal sinus
3.Cavernous Sinus
(1) Position: lying on each side of sella turcica
(2) Contents: internal carotid artery & abducent nerve
run through it ; and oculomotor,trochlear,
ophthalmic(V1) & maxillary(V2) nerves pass
through its lateral wall into the orbit.
(3) Communication: facial v –-superior & inferior
ophthalmic veins—--cavernous sinus
(4) Clinical significances: bacterial or viral infection
in the dangerous facial trigone may spread to
the sinus via the above pathway causing sepsis
& thrombosis in it and even negtively affecting
the ajacent crainal nerves,in which relative
symptoms & signs will appear.
Cerebrospinal Fluid(CSF)
1.Producing Position
CSF is secreted by the choroid
plexuses in all ventricles.
2. Circulation
R&L lateral ventricles
↓interventricular
↓foramina
third ventricle
↓ cerebral aqueduct
fourth ventricle
↓ R/L lateral foramina
↓ median foramen
subarchnoid space
↓ arachnoid granulations
superior sagittal sinus
↓
internal jugular vein
3.Clinical Significances
If the pathways of CSF circulation are
blocked, CSF will not be able to return to
the epidural sinuses, and will stagnate in
cerebral ventricular system, leading to the
swellen brain (hydrocephalus) especially in
infants or children and to a high intrcranial
pressure in adults in which the disfunctions
of brain or cerebral hernias may appear,
resulting to sudden death. .
Blood Vessels in CNS
Arteries of CNS
I. Brain Arteries
1.Origin
two sets of arteries
internal carotid artery
vertebral artery
2. Branches of Internal Carotid Artery
(1) anterior cerebral a
(2) middle cerebral a
(3) anterior choroidal a
(4) optic a
(5) posterior communicating a
The above branches of the artery collectively
provide blood for the anterior 2/3 part of cerebral
hemisphere including eyes, & anterior portion of
thalamus.
(1)Anterior cerebral a supplies the medial surface of
cerebrum & upper part of dorsal surface of the cerebrum.
(2)Middle cerebral a supplies most part of the
dorsolateral surface of cerebral hemisphere.
(3) anterior
choroidal a
(4) optic a
(5) posterior
communicating a
The three branches
supply the areas with
the same arterial names.
3. Cerebral Arterial Circle(Willis`s)
1) Composition(5 parts, 9 branches ): anterior communicating A，
bilateral anterior cerebral As, bilateral internal carotid As，
bilateral posterior communicating As, bilateral posterior cerebral As.
2) Location:
The circle lies on
inferior surface of
cerebrum & encircles
optic chiasma,
tuber cinereum &
mammillary bodies.
3)Functions：
The circle regulates
blood flow of both
cerebral hemispheres.
4.Two Kinds of
Arterial Branches
Anterior ,middle and
posterior cerebral arteries
and the cerebral arterial
circle all possesses
the following:
cortical branches
central branches (IC,BN)
Few anastomoses exist among
separate branches . If a branch
is blocked or broken, the target
area suffers a deadly attact,either
stroke or bleeding, resulting in
losses of sensation & paralyses.
5. Clinical Significances
1. The branches of cerebral arteries hardly establish
anastomoses (so-called terminal As ). When one of them is
blocked, the supplied regions of brain will completely lack
blood supply, leading to neuronal necroses & apoptoses .
2. The arteries of brain seldom beat, which may link to
their thin walls & their curved routes, bringing about no
palpable pulses from the arteries.
3. The branches for internal capsule are easily broken and
this may result in a worse bleeding, because they directly
arise from middle cerebral A at a right angle and and their
walls have to put up with the powerful rush force and
high blood pressure from torrent blood flow.
II.Arteries of Spinal Cord
1.Four Origins
Vertebral A
Ascending cervical A
Intercostal A
Lumbar A
2. Branches of Vertebral
Artery & Basilar Artery
(1)anterior spinal artery (1)
Artery (1) ~ artery (5) are the
(2) posterior spinal arteries (1)
(3) posterior inferior cerebellar arteries (2) branches of vertebral artery
(4) anterior inferior cerebellar arteries (2)
(5) labyrinthine arteries (2)
(7) pontine arteries (3 or 4 pairs )
Artery (7)~ Artery (9) are the
(8) superior cerebellar arteries (2)
branches of basilar artery
(9) posterior cerebral arteries (2)
The above branches collectively provide blood for
the posterior 1/3 portion of cerebral hemisphere and
posterior part of thalamus
as well as the cerebellum, brain stem & spinal cord.
posterior cerebral A.
superior cerebellar A
pontine A
labyrinthine A
Ant.inf cerebellar A
Ant.spinal A
Vertebral A
Post.inf.cerebellar A
3.It supplies most parts of occipital and temporal lobes.
Post.cerebral A
Basillar A
Ant.
spinal A
Vertebral A
Ascending
cervical A
Post.
Intercostal A
Lumbar A
Post.
Spinal A
Post spinal A
4.Arterial Distribution
Patterns in Spinal Cord
Ant. Spinal A
Coronary A of spinal cord
III.Veins of Brain
1. Features
(1) They own no relatively accompanying arteries.
(2) There are two sets----superficial and deep veins.
2.Division
(1) Superficial Vein ( 3 branches : sup, mid & inf )
They lie on the surface of the cerebrum and drains
the blood from the cerebral cortex to venous sinuses :
a. superior cerebral v (on the surface above LS )
→superior sagittal sinus
b. middle cerebral v (situated in lateral sulcus--LS )
→cavernous sinus
c. inferior cerebral v (on the surface under LS )
→cavernous sinus & transverse sinus
Superior cerebral V
Sup.sagittal sinus
Middle cerebral V
Inferior cerebral V
Transverse sinus
Sigmoid sinus
(2)Deep veins drain the blood from the deep
medullar matter to venous sinuses:
a.Internal cerebral V
b.Great cerebral V
straight sinus
(lying in postoinferior
part of corpus callosum)
c.Basilar V.
Great cerebral
vein is also called
Galen`s vein.